The lithium-sulfur battery has been considered as one of the potential candidates for energy storage devices owing to its high theoretical specific capacity and superior energy density. However, its practical application still faces challenges such as low sulfur utilization, the serious shuttle effect of polysulfides and large volume expansion, especially upon high areal sulfur loading. Herein, conductive cobalt doped niobium nitride (Co-NbN) porous spheres as a novel kind of sulfur host material have been fabricated via a facile solvothermal and subsequent calcination process under ammonia. The obtained Co-NbN/rGO/S cathode delivers an excellent rate performance of up to ∼600 mA h g⁻¹ at 1C with a relatively high areal loading of 3.3 mg_s cm⁻² and an excellent long–term cycle stability of 404.5 mA h g⁻¹ after 800 cycles at 1C (the decay rate is only 0.07% per cycle) with a sulfur loading of 72%. It is worth noting that the cathode exhibited a superior areal capacity of 3.92 mA h cm⁻² at a high sulfur loading of 5.6 mg_s cm⁻² with a lean electrolyte (E/S = 8 μL mg_sulfur⁻¹). It is considered that the conductive and polar niobium nitride could effectively improve sulfur utilization and polysulfide anchoring of the sulfur cathode, and its unique porous structure could effectively accommodate the distribution of the sulfur species and inhibit volume expansion of the cathode. In addition, the synergistic effect between cobalt and NbN further facilitated the conversion of sulfur species, suppressing the shuttle effect and accelerating electrochemical kinetics. The porous Co-NbN based host material has great potential for practical application in lithium-sulfur batteries.

中文翻译：

---

导电钴掺杂氮化铌多孔球体作为高级锂硫电池的高效多硫化物转化剂

锂硫电池由于其高的理论比容量和优越的能量密度而被认为是储能设备的潜在候选者之一。然而，其实际应用仍然面临诸如硫利用率低，多硫化物的严重穿梭效应和大体积膨胀的挑战，特别是在高面积硫负荷下。本文中，已经通过一种容易的溶剂热和随后在氨气下的煅烧工艺，制备了导电钴掺杂氮化铌（Co-NbN）多孔球体作为一种新型的硫基质材料。所获得的Co-NbN / rGO / S阴极在1C时具有高达〜600 mA hg ^-1的优异速率性能，并且具有3.3 mg _s cm ^-2的相对较高的面负载硫含量为72％时，在1C下进行800次循环后，其出色的长期循环稳定性为404.5 mA hg ^-1（每循环衰减率仅为0.07％）。值得注意的是，阴极表现出3.92毫安高厘米优异的面积容量^-2在5.6毫克高载硫量_小号厘米^-2与贫电解质（E / S = 8μL毫克_硫^-1）。认为导电和极性氮化铌可以有效地提高硫阴极的硫利用率和多硫化物锚定，并且其独特的多孔结构可以有效地容纳硫物种的分布并抑制阴极的体积膨胀。此外，钴和NbN之间的协同作用进一步促进了硫物质的转化，抑制了穿梭效应并加速了电化学动力学。多孔的基于Co-NbN的基质材料在锂硫电池中具有实际应用的巨大潜力。